Embedding Carbon Nanotubes Within Spacesuits to Protect Astronauts Against the Dangers of Space

10 min readJun 1, 2022

In 1983, the first spacewalk was conducted by Story Musgrave and Donald Peterson. Flash forward about 40 years later, astronauts are conducting spacewalks with the same space suits. These spacesuits were expected to last 15 years yet we are still using them. It is important to note that these space suits are showing their wear and tear such as the cancellation of the all-female spacewalk due to the malfunctioning of the suits. The spacesuit, from its existence, has become a symbol of the future. The future being space and the suit gives the feeling that we can explore it. We have seen advancements in both the technology and looks that astronauts wear within space shuttles, but there has been a lack of advancements in the suits that astronauts wear directly in the cold vacuum of space.

The suits worn today on spacewalks for the International Space Station are called Extravehicular Mobility Units (EMU). They allow an astronaut to be in space for 6.5 to 8 hours. The EMUs have a combination of 17 layers and a pressurized environment to allow an astronaut to carry out all sorts of tasks. The function of the EMUs is to create a breathable atmosphere, allow for mobility, control temperature, and protect from radiation and particle impacts. They play the role of acting as a personal spacecraft, assisting in the astronauts’ survival.

The problem with these space suits is that they are annoyingly bulky. This bulkiness is due to the pressure within a spacesuit. These suits need to be kept at 0.3 psi to protect against any micrometeoroids that may hit the suit and puncture a hole. The pressurizing of the suit causes the suit to inflate due to the pressure differential, the pressure difference between the inside and outside of the suit. The pressure in the suit increases the strength of the top layer, adding to the barrier of protection. Therefore, the more you increase the pressure, the more protection you have against micrometeoroids that may be hurdling at you at speeds up to 225000 mph. The problem with the increased pressure is the lack of mobility. The increased pressure on your limbs increases the resistance to movement. It is almost like fighting the wind on a windy day, it takes more time to get to your destination, therefore wasting more energy. With more pressure, astronauts risk not being able to complete essential tasks needed. This can waste resources and time.

By decreasing pressure to allow for more mobility, not only do you risk damage from an asteroid but decompression sickness as well. The nitrogen that we breathe in the air is unable to dissolve in the tissue and blood completely. These bubbles are harmful in two ways. The first way is that these bubbles may continue expanding causing internal injuries to tissue. The second way is that these bubbles can go into important vessels, causing blood clots or directly blocking blood to go into the vessel. The possible side effects include dehydration, fatigue, and in worst cases, death.

Spacesuits aren’t only supposed to protect astronauts from obstacles we can see but the deadly hidden dangers as well. While in space, there is no atmosphere to protect one from the radiation coming from space. This leaves one susceptible to radiation from solar flares, gamma cosmic rays, and high-energy protons traveling throughout space. Our current spacesuits can only protect astronauts from the radiation of 155 -250 MeV. This leaves minimal to no protection against high-energy radiation such as gamma and X-rays. Side effects may include radiation sickness, the increased lifetime risk for cancer, central nervous system effects, and degenerative diseases (source). Opaque layers and visors treated with a UV coating are used to combat minimal levels of radiation. Due to the lack of protection, the spacewalks have to be timed to fall when there is minimal radiation activity. This still leaves some risk of unknown exposure to radiation and can be dangerous in case of emergencies where there are critical repairs needed to be made.

Overall, space poses physical obstacles of micrometeoroids hurtling through space at fast speeds, threatening the integrity of suits. It also poses the obstacle of exposure to X-ray radiation. Space is a dangerous place, and public organizations and private companies are entrusted with the lives of astronauts. Therefore, there are high standards for when it comes to a spacesuit. The problem lies in the fact that the spacesuits used today on missions and spacewalks are from 1983, therefore not incorporating recent advancements in material science. We can reduce the bulkiness of suits and provide protection from x-ray radiation, through the use of a nanomaterial called carbon-nanotubes. These carbon nanotubes are embedded with nanoparticles from a certain metal called bismuth oxide.

What are Carbon Nanotubes?

Before I go into carbon nanotubes, I’m going to do a brief exposure to nanotechnology, the category carbon nanotubes fit under in terms of material. Feel free to skip the next paragraph where I deep dive into nanotechnology.

Nanotechnology works on the nanoscale (10^-9), as hinted by its name. Comparing a nanometer to the diameter of a single strand of human hair, that is 80,000- 100,000 nanometers. The advantage of working on the nanoscale changes in the properties of materials due to the property’s size dependency. The properties also change due to quantum effects, larger surface area, and self-assembly. Properties such as melting point, fluorescence, electrical conductivity, magnetic permeability, and chemical reactivity change on the nanoscale. This allows for properties such as increased strength.

Carbon Nanotubes are a type of nanomaterial known for their strength. To break down the name of a carbon nanotube, the carbon part of the word signals the fact that this material is made up of carbon atoms arranged in a hexagonal pattern called aromatic rings. This hexagonal pattern forms graphene molecules. Several graphene molecules (aka the carbon hexagonal atoms) are lined up together in a lattice formation to form a tube-shaped molecule, hinting at the second part of the name carbon nanotubes. Due to it being a nanomaterial, carbon nanotubes are small in size, being one micron long and a diameter of nanometers.

Carbon nanotubes are closely related to graphene in terms of properties and chemical makeup due to the fact they are both made up of carbon. The arrangement of the carbon atoms is the same used in graphene. Carbon nanotubes are basically rolled-up sheets of graphite. One can credit carbon nanotubes’ strength due to their graphene similarities.

Carbon nanotubes are 117x stronger than steel. When comparing a material’s strength to carbon nanotubes, carbon nanotubes have a higher elastic modulus of 1000 GPa. The elastic modulus is related to the tensile strength. The tensile strength is the maximum stress that a material can withstand before it breaks. One can measure the tensile strength by stretching a material through a tensile test. Comparing how steel performs under a tensile test is different for carbon nanotubes due to the bonds between the carbon atoms and the size of the carbon nanotubes. When steel is put under this tensile test, it develops microtears that grow as the result of more stress placed on the steel, eventually completely fracturing the former microtears. An important note to keep in mind is that steel is made up of several molecules. Due to the fact that carbon nanotubes are a molecule, it doesn’t develop weak points from crystalline grains that join molecules together. Carbon nanotubes also have a special structure called the SP2 hybridization. The main takeaway from this structure is that the carbon molecules have a double arrangement which makes it harder to develop microtears.

Radiation Protection

The x-ray shielding properties of the carbon nanotubes are based on the Compton effect, a type of photon interaction. The Compton effect causes x-rays of radiation to scatter on a material. In other words, the initial x-ray changes its initial trajectory, heading in a direction outwards. The Compton effect is the result of the interaction of the photon with either a free electron or a loosely bound valence electron. This result causes the material to absorb some of the energy while changing the wavelength of the photon. The carbon nanotubes are able to replicate this effect, due to the embedding of bismuth oxide nanoparticles. Bismuth oxide is the result of the metal, bismuth losing an electron. Bismuth oxide has several free electrons in its outer shells, which increases the probability of the effect occurring. Nanoparticles are a category within nanotechnology that are nanosized particles. Bismuth oxide nanoparticles are highly mobile in a free state. Bismuth oxide is special for its dielectric, or insulating, properties, which are helpful in absorbing the energy in the Compton effect. During the Compton Effect, the absorbing electron becomes ionized, but bismuth oxide’s insulating properties decrease the probability of the ionization occurring. The carbon nanotubes structure also assists in this process as they are multi-walled carbon nanotubes, allowing the energy to be reduced faster (aka energy attenuation).

These carbon nanotubes can be weaved into a fabric called buckypaper. This paper is made up of 95% carbon nanotubes. Buckypaper is made similarly to making paper out of newspaper. Carbon nanotubes are suspended in water through the use of chemicals (ex: NanoSperse AQ surfactant) which also helps in stabilizing the carbon nanotubes. The suspended carbon nanotubes are then filtered onto membrane support to provide structure to the paper and hold its shape, while the paper dries. Then the support is removed once dried, leaving a free-standing buckypaper. This paper would then be used within the spacesuit as the top layer or second to top layer of the suit, to allow for the electromagnetic radiation waves to bounce off in other directions.

Proposal

Hypothesis: Buckypaper made out of multiwalled carbon nanotubes embedded with bismuth oxide nanoparticles will be able to shield against x-ray radiation and protect against micro asteroid impacts of up 55 GPa in pressure.

Testing

When testing this paper, a series of tests would need to be performed to test durability over time, damage after impact with micrometeoroids, and exposure to x-ray radiation.

Strength Testing

An 18-gauge needle will be used to replicate the puncturing ability of micro asteroids in space. The needle will be lowered into the material with a robotic arm, slowly increasing the force used to puncture the material. These tests will be run 12 times on a new piece of fabric each time.

A second test will be performed to measure the impacts of different pressures applied to buckypaper. The weight will be incrementing at 5 GPa, starting at 25 GPa and going until 70 GPa, or when a fracture occurs. This test will also be run 12 times on a new piece of fabric during each test.

Durability Testing

A single buckypaper pressure of 55 GPA will be applied several times until a tear is discovered in the fabric. Fraying and displacement of the fabric will be observed during testing to see the durability of the fabric. This test will be run 12 times on a new piece of fabric for each test.

X-ray Radiation

The radiation from space will be simulated in a galactic cosmic rays simulator (GCR simulator). Beams of ions will be exposed to the buckypaper material. The specific wavelength to the buckypaper will be exposed falls in energies that range from 145 eV to 124 keV. A Geiger counter, a radiation measuring device, will be used to check the radiation levels before and after the exposure to the ion beam.

Further Testing

A phase of testing may be taken to the ISS to see how the buckypaper reacts in a microgravity environment and notice any similarities or differences.

Conclusion

It is important to note that carbon nanotubes do have high manufacturing costs and it is also harder to produce carbon nanotubes in large amounts. While carbon nanotubes pose their own challenges, these gaps in the technology won’t be as big of problems with the development in technology. Carbon nanotubes have become a field of interest for many, therefore creating a demand for advancements in carbon nanotubes.

The constant iteration of space suits allows for further exploration of space. While undervalued, space suits are a crucial part of the journey. With different parts of space bringing their own challenges we must continually innovate. Each different celestial body brings its own challenges such as the Moon with lunar dust or Mars with an unbreathable atmosphere. Further development in spacesuits allows for further exploration in space allowing us as a society to develop. Take the internet, for example, it has allowed people to connect around the world and changed how we conduct business. Spacesuits are trivial vessels that carry the most precious thing in our universe, human life.

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